Conical hybrid FDB motor

Abstract

A disc drive design comprising a shaft and sleeve supported for relative rotation by a journal type fluid dynamic bearing utilizing grooves on one of the shaft or sleeve surfaces. At least a part of the shaft is generally conical in cross-section, so that a downward force component is developed to balance upward pressure on end of shaft; this conical region typically includes a fluid dynamic bearing (grooves being on either the shaft or sleeve). A grooved pattern of a design similar to that usually found on a thrust plate may be defined on an axial end surface of the shaft or the counterplate facing the axial end of the shaft, so that thrust is created to maintain separation of the end of the shaft and the facing counterplate plate during relative rotation. A diamond-like coating (DLC) may be applied to the counterplate surface or to the end of the shaft; further, either the counterplate or shaft may be made out of ceramic material to enhance this performance. This coating may also be applied to the conical surface of the shaft or the facing surface of the sleeve.

Description

CROSS REFERENCE TO A RELATED APPLICATION[0001]This application claims priority to a provisional application Ser. No. 60 / 342,681 filed Dec. 20, 2001, in the names of Anthony Joseph Aiello, Klaus Dieter Kloeppel and provisional application 60 / 424,212 filed Nov. 5, 2002, in the names of Jeffry Arnold LeBlanc, Alan Lyndon Grantz, Troy Michael Herndon, Michael David Kennedy, Robert Alan Nottingham, entitled Single Core FDB Motor for HDD Applications, which application is incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to fluid dynamic bearing motors, and more particularly to such motors without thrust plate.BACKGROUND OF THE INVENTION[0003]Disc drive memory systems have been used in computers for many years as storage space for digital information. Information is recorded on concentric memory tracks of magnetic discs that rotate around a spindle. Information is accessed by read / write heads located on a pivoting arm which moves radially over the surface...

AI Technical Summary

Benefits of technology

[0026]In another embodiment, a recirculation or pressure equalization port is provided from the gap between shaft end and counterplate to a region between the conical bearing a

Problems solved by technology

The conventional bearing system described above is prone, however, to several shortcomings.

First, vibration is generated by the balls rolling on the raceways.

Ball bearings used in hard disk drive spindles run under conditions that often cause physical contact between raceways and balls in spite of the lubrication layer provided by the bearing oil or grease.

This vibration results in misalignment between the data tracks and the read/write transducer.

These imperfections reduce the lifetime and effectiveness of the disc drive system.

Another problem is related to the use of hard disk drives in portable computer equipment and the resulting requirements for shock resistance.

Since the contact surface in ball bearings is very small, the resulting contact pressures may exceed the yield strength of the bearing material and leave permanent deformation and damage on raceways and balls.

Moreover, mechanical bearings are not always scaleable to smaller dimensions.

This is a significant drawback since the tendency in the disc drive industry has been to continually shrink the physical dimensions of the disc drive unit, as well as operate the units at ever-increasing speeds.

Another problem is that of potential leakage of grease or oil into the atmosphere of the disc drive, or outgassing of the components into this atmosphere.

Because of the extremely high tolerance required for smaller radial spacing between tracks on the disc and the gap in the transducer which is used to read and write data on the disc, discs are located within sealed housings in which contaminants cannot be tolerated.

However, air cannot provide the lubricating qualities of oil or the load capacity.

The liquid lubricant must be sealed within the bearing to avoid a

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